The next seminar “Modelling of materials – theory, model reduction and efficient numerical methods” will take place next Wednesday (May 26, 2021) from 9:00 till 10:00. The talk will be given by Šimon Midlík and Jakub Kvorka. Please see the details below.

Speakers: **Šimon Midlík** and **Jakub Kvorka**

Title: **Theoretical and experimental approach to superfluid 4He**

Abstract: In reaction to a newly started collaboration between members of the Mathematical Institute (division of Mathematical modelling), Department of geophysics, and Low-temperature physics department via the START project “Novel multiscale approach to the dynamics of superfluid helium”, we would like to introduce each member’s work to a wider audience.

In this talk we plan to introduce the basics of current theoretical models, vortex-filament method (VFM) and Hall-Vinen-Bekarevich-Khalatnikov model (HVBK), describing dynamics of superfluid 4-helium. We will further present some currently ongoing experiments in the laboratory of superfluidity. These experiments are to be understood by methods of mathematical modeling and numerics. In particular, we will present preliminary data on the second-sound waves in helium analyzed by means of the decomposition to spherical harmonics, which is a common numerical technique in geophysics.